The invention relates to a method for producing a battery module having a plurality of battery cells. Furthermore, the invention relates to a battery module having a plurality of battery cells.
Battery modules are used to provide high-voltage batteries for electric vehicles and hybrid vehicles and include each a plurality of battery cells. Normally, the battery cells in such a battery module are electrically connected with each other and subjected to a compressive force which prevents bulging of walls of cell housings of the individual battery cells. In such battery modules, prismatic battery cells are oftentimes used and arranged side-by-side so as to be electrically connectable with one another in a simple manner. Since the prismatic battery cells usually have cell housings of metal, it is necessary to electrically insulate the battery cells from each other. In certain operating modes, provision is further made for a thermal insulation between the battery cells. Plastics are oftentimes used for electrical and thermal insulation.
When using plastic parts as separating elements between the individual battery cells, also referred to as spacers, many individual parts are required for the construction of battery modules with a plurality of battery cells. This is relatively complicated.
DE 10 2010 038 862 A1 describes a method for the production of a battery module, in which a plurality of battery cells are initially provided, and then the battery cells are electrically interconnected by cell connectors. Thereafter, a plastic housing of the battery module is manufactured by encapsulating the individual battery cells with plastic. As a result, gaps between the battery cells are filled with plastic using an injection molding process, and a sheath is produced which surrounds the battery cells in their entirety during the injection molding process. Thus, a single-piece plastic sheath is formed which delimits the battery module to the outside as housing. Only the connections or terminals of the battery module project out from the plastic sheath so as to be accessible from outside.
Such a method is difficult to implement, when the battery cells must be subjected to a compressive force in order to prevent bulging of the cell housings. In a situation in which the battery cells are pressed against each other, it is difficult to introduce plastic into the gaps between the battery cells. In addition, curing of the plastic material becomes difficult, as this requires long curing times. Heating for accelerating curing is not feasible, since the battery cells should not be exposed to a corresponding increase in temperature.
Furthermore, DE 20 2010 004 637 describes a lead-acid battery, as used as starter battery in motor vehicles. The lead-acid battery includes a plastic housing with several chambers which are formed or delimited by intermediate walls. Lead plates are arranged in the chambers as electrodes. Subsequently, the plastic housing is closed with a lid which is preferably formed as an injection-molded part. Electrolyte is then filled via feed openings, provided in the lid, into the battery so that it can be charged and discharged. Preferably, the housing and the lid are made of a pressure-resistant and impact-resistant plastic material, such as polypropylene.